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Chatzieleftheriou M, Kowalski A, Berović M, Amaricci A, Capone M, De Leo L, Sangiovanni G, De' Medici L. Mott Quantum Critical Points at Finite Doping. PHYSICAL REVIEW LETTERS 2023; 130:066401. [PMID: 36827570 DOI: 10.1103/physrevlett.130.066401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
We demonstrate that a finite-doping quantum critical point (QCP) naturally descends from the existence of a first-order Mott transition in the phase diagram of a strongly correlated material. In a prototypical case of a first-order Mott transition the surface associated with the equation of state for the homogeneous system is "folded" so that in a range of parameters stable metallic and insulating phases exist and are connected by an unstable metallic branch. Here we show that tuning the chemical potential, the zero-temperature equation of state gradually unfolds. Under general conditions, we find that the Mott transition evolves into a first-order transition between two metals, associated with a phase separation region ending in the finite-doping QCP. This scenario is here demonstrated solving a minimal multiorbital Hubbard model relevant for the iron-based superconductors, but its origin-the splitting of the atomic ground state multiplet by a small energy scale, here Hund's coupling-is much more general. A strong analogy with cuprate superconductors is traced.
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Affiliation(s)
- Maria Chatzieleftheriou
- Laboratoire de Physique et Etude des Matériaux, UMR8213 CNRS/ESPCI/UPMC, 75005 Paris, France
| | - Alexander Kowalski
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Maja Berović
- International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy
| | - Adriano Amaricci
- CNR-IOM DEMOCRITOS, Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Via Bonomea 265, I-34136 Trieste, Italy
| | - Massimo Capone
- International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy
- CNR-IOM DEMOCRITOS, Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Via Bonomea 265, I-34136 Trieste, Italy
| | - Lorenzo De Leo
- Laboratoire de Physique et Etude des Matériaux, UMR8213 CNRS/ESPCI/UPMC, 75005 Paris, France
| | - Giorgio Sangiovanni
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Luca De' Medici
- Laboratoire de Physique et Etude des Matériaux, UMR8213 CNRS/ESPCI/UPMC, 75005 Paris, France
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Lenihan C, Kim AJ, Šimkovic F, Kozik E. Evaluating Second-Order Phase Transitions with Diagrammatic Monte Carlo: Néel Transition in the Doped Three-Dimensional Hubbard Model. PHYSICAL REVIEW LETTERS 2022; 129:107202. [PMID: 36112452 DOI: 10.1103/physrevlett.129.107202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Diagrammatic Monte Carlo-the technique for the numerically exact summation of all Feynman diagrams to high orders-offers a unique unbiased probe of continuous phase transitions. Being formulated directly in the thermodynamic limit, the diagrammatic series is bound to diverge and is not resummable at the transition due to the nonanalyticity of physical observables. This enables the detection of the transition with controlled error bars from an analysis of the series coefficients alone, avoiding the challenge of evaluating physical observables near the transition. We demonstrate this technique by the example of the Néel transition in the 3D Hubbard model. At half filling and higher temperatures, the method matches the accuracy of state-of-the-art finite-size techniques, but surpasses it at low temperatures and allows us to map the phase diagram in the doped regime, where finite-size techniques struggle from the fermion sign problem. At low temperatures and sufficient doping, the transition to an incommensurate spin density wave state is observed.
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Affiliation(s)
- Connor Lenihan
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
| | - Aaram J Kim
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
- Department of Physics, University of Fribourg, Chemin du Musée 3, 1700 Fribourg, Switzerland
| | - Fedor Šimkovic
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
- CPHT, CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - Evgeny Kozik
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
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Maryati Y, Winarsih S, Syakuur MA, Manawan M, Saragi T. Structural Properties and Hopping Conduction in the Normal State of Electron-Doped Superconductor Cuprate Eu 2-x Ce x CuO 4+α-δ. ACS OMEGA 2022; 7:12601-12609. [PMID: 35474784 PMCID: PMC9026046 DOI: 10.1021/acsomega.1c06161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Electron-doped superconducting cuprate of Eu2-x Ce x CuO4+α-δ has been studied in the whole doping regime from x = 0.10-0.20 with reducing oxygen content to investigate the relation between the crystal structure and the hopping conduction in the normal state. Parameter of the crystal structure has been extracted from the X-ray diffraction (XRD) measurement while hopping conduction parameters have been obtained from resistivity measurements. The Eu-O bond length decreases with the increasing doping concentration, indicating the successful doping by the partial replacing of Eu3+ with Ce4+. The resistivity increases with decreasing temperature in all measured samples. This is an indication of bad metal-like behavior in the whole regime in the normal state of electron-doped superconducting cuprate of Eu2-x Ce x CuO4+α-δ. The temperature dependence of resistivity was analyzed by the Arrhenius law and the variable range hopping model. It is found that the hopping conduction mechanism more likely follows the variable range hopping rather than the Arrhenius law, indicating that the hopping mechanism occurs in three dimensions. The Cu-O bond length probably plays an important role in decreasing the activation energy. The decreasing value of the activation energy correlates with the increase in the localization radius.
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Affiliation(s)
- Yati Maryati
- Department
of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km. 21, Sumedang 45363, West Java, Indonesia
| | - Suci Winarsih
- Department
of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km. 21, Sumedang 45363, West Java, Indonesia
| | - Muhammad Abdan Syakuur
- Department
of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km. 21, Sumedang 45363, West Java, Indonesia
| | - Maykel Manawan
- Faculty
of Defense Technology, Indonesia Defense
University, Bogor 16810, West Java, Indonesia
| | - Togar Saragi
- Department
of Physics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km. 21, Sumedang 45363, West Java, Indonesia
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Lenihan C, Kim AJ, Šimkovic Iv F, Kozik E. Entropy in the Non-Fermi-Liquid Regime of the Doped 2D Hubbard Model. PHYSICAL REVIEW LETTERS 2021; 126:105701. [PMID: 33784123 DOI: 10.1103/physrevlett.126.105701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
We study thermodynamic properties of the doped Hubbard model on the square lattice in the regime of strong charge and spin fluctuations at low temperatures near the metal-to-insulator crossover and obtain results with controlled accuracy using the diagrammatic Monte Carlo method directly in the thermodynamic limit. The behavior of the entropy reveals a non-Fermi-liquid state at sufficiently high interactions near half filling: A maximum in the entropy at nonzero doping develops as the coupling strength is increased, along with an inflection point, evidencing a metal to non-Fermi-liquid crossover. The specific heat exhibits additional distinctive features of a non-Fermi-liquid state. Measurements of the entropy can, therefore, be used as a probe of the state of the system in quantum simulation experiments with ultracold atoms in optical lattices.
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Affiliation(s)
- Connor Lenihan
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
| | - Aaram J Kim
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
| | - Fedor Šimkovic Iv
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
- Centre de Physique Théorique, École Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - Evgeny Kozik
- Department of Physics, King's College London, Strand, London WC2R 2LS, United Kingdom
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Phillips P. Normal state of the copper oxide high-temperature superconductors. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:1572-1573. [PMID: 21422015 DOI: 10.1098/rsta.2011.0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Philip Phillips
- Loomis Laboratory of Physics, University of Illinois, Urbana, IL 61801, USA.
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